Piezoelectric haptic actuator integration

ABSTRACT

User interface experiences with electronic devices are enhanced with feedback cues such as haptic or vibrotactile output feedback. One or more piezoelectric actuators generate haptic output. The one or more piezoelectric actuators may be integrated onto a display substrate, a battery case, a device enclosure, or other component. Such integration may improve propagation of the haptic output to the user, reduce bulk of the electronic device, minimize parts count, and reduce production costs.

BACKGROUND

User interfaces for electronic devices traditionally engage a limitednumber of human senses. Users see images presented on displays, and hearsounds generated by speakers, but physical feedback has been limited tosimple shakes or buzzes. Furthermore, in addition to having limitedoutput capabilities, traditional mechanisms are bulky, rendering themdifficult to incorporate into small form-factor devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is set forth with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different figures indicates similaror identical items.

FIG. 1 depicts an electronic device having a display, a touch sensor,and an integrated haptic stack.

FIG. 2 is a block diagram of example internal components of anillustrative electronic device, such as the device of FIG. 1.

FIGS. 3A and 3B depict cross sections of an integrated haptic stack witha piezoelectric haptic actuator on a display substrate.

FIGS. 4A and 4B illustrate cross sections of an integrated haptic stackwith a piezoelectric haptic actuator on a haptic substrate.

FIG. 5 depicts a plan view of a single piezoelectric haptic actuator ona substrate.

FIG. 6 depicts a plan view of dual piezoelectric haptic actuators on asubstrate.

FIG. 7 depicts a plan view of six piezoelectric haptic actuators on asubstrate.

FIG. 8 depicts a plan view of five piezoelectric haptic actuators withdifferent geometries on a substrate.

FIG. 9 depicts a plan view of additional geometries of piezoelectrichaptic actuators on a substrate.

FIG. 10 illustrates a process of forming a haptic stack.

DETAILED DESCRIPTION Overview

Electronic devices such as cellular phones, portable media players,tablet computers, netbooks, laptops, personal computers, cash registers,electronic book (“eBook”) readers, input devices, and so forth,incorporate user interfaces to allow users to interact with them.Further, engaging various senses of the user tends to provide a moreinteractive and satisfying experience for the user. For instance,display screens provide visual output while speakers provide audiooutput. However, haptic (or “vibrotactile”) output has been limited.Traditional haptic output components provide coarse haptic output suchas buzzes or vibrations. For example, a typical haptic output componentmay consist of a vibrator with a rotary motor coupled to an eccentricweight that, when spun, generates a vibration.

The following discussion, meanwhile, describes piezoelectric hapticactuators and techniques to use these piezoelectric haptic actuators togenerate haptic output. Audio output devices, such as speakers, areconfigured to compressively modulate an ambient fluid such as air orwater. While a speaker generating a high amplitude audio output mayimpart some vibration on a speaker enclosure, the purpose of the speakeris to produce audible output rather than move or deform the speakerenclosure. In contrast, the haptic output devices described are designedto impart a physical dislocation of and/or transfer of momentum to asolid or semi-solid structure.

As discussed herein, the piezoelectric haptic actuators are configuredto generate a physical force and impart a transfer of momentum betweenat least two components of a device or a dislocation or deformation of aportion of the device. For example, in one implementation where momentumtransfer is used, when the user is touching the device the user feelsthe transfer of momentum as the haptic output. In another implementationwhere dislocation or deformation is used, the user may feel the actualdislocation or deformation, such as a bump or ridge on the display.

The following discussion also describes techniques for incorporatingthese actuators into integrated haptic stacks. In some implementations,the piezoelectric haptic actuators share a substrate with anothercomponent. For example, the piezoelectric haptic actuator may bedisposed on one side of an existing substrate, such as a non-displayside of a display substrate, a portion of a battery casing, a deviceenclosure, and so forth. Once assembled, this arrangement comprises anintegrated haptic stack. Such integration reduces bulk, minimizes partscount, and may also reduce production costs.

In other implementations, the piezoelectric haptic actuator may bedisposed upon a haptic substrate, and placed adjacent to or betweenother components. Such emplacement results in a variation of theintegrated haptic stack.

Piezoelectric materials expand, contract, or both upon the applicationof an electric field. For example, but not by way of limitation,piezoelectric materials include various crystals such as quartz,ceramics such as lead zirconate titanate, and polymers such aspolyvinylidene fluoride and ionic polymer-metal composites. Applying anelectric field to the piezoelectric material results in an alteration ofthe shape of the material and generation of a physical force. Theresulting physical force produces haptic output, suitable for userfeedback.

This haptic output may enhance a user interface of an electronic deviceby enhancing a user's experience with the device. For example, considera user interacting with a touch sensitive display, or touchscreen, on anelectronic device. Without haptic output, the user's selection of anobject such as a virtual button on the screen via touch is limited tovisual cues, such as changing the color of the selected object, and/orauditory cues, such as playing a sound. With haptic output, such asgenerated via the piezoelectric haptic actuators described below, theuser may experience a variety of tactile effects. For example, the usermay be able to actually feel in their fingertips what seems to resembleedges of the button on the display screen. Likewise, the user placingadditional pressure on the object may result in haptic output resemblingthe physical depress and click of a mechanical button, reaffirming theuser's selection of that button.

In the implementations described in detail below, an electronic devicemay integrate one or more piezoelectric actuators in one of severalconfigurations. In one configuration, the piezoelectric actuators areaffixed to a substrate that also serves as a substrate for othercomponents of the device to form an integrated haptic stack. In thisconfiguration, the substrate performs an additional function, such asacting as a substrate for a display, casing for a battery, portion ofthe enclosure containing the electronic device, and so forth. In anotherconfiguration the piezoelectric actuators are affixed to a dedicatedhaptic substrate to form a haptic assembly. The haptic assembly may thenbe incorporated with other components such as the display, battery, andso forth to form the integrated haptic stack.

Regardless of whether or not the substrate is shared with anothercomponent of the device, the piezoelectric haptic actuators may resideon the substrate in a variety of arrangements. The count, distribution,and geometry of the actuators may be adjusted to account for variationsin compliance of the substrate, desired output characteristics, and soforth. The count of piezoelectric haptic actuators may vary from asingle element to an array on the substrate. Actuators may bedistributed on the substrate as a regular matrix or in variouspositions. Each of the piezoelectric haptic actuators may manifest inone of many possible geometries. For example, actuators may be circular,elliptical, polygonal, and so forth on the substrate.

Each of the piezoelectric haptic actuators couple via electricalconductors, such as wires or circuit traces, to a haptic controller. Thehaptic controller is configured to output the electrical signals thatgenerate the piezoelectric effect within the piezoelectric material,thus producing a haptic output. In some implementations thepiezoelectric haptic actuators may be independently addressable by thehaptic controller, such that one or more specified actuators generateoutput while other non-specified actuators remain inactive.

Illustrative Touch-Screen Device

FIG. 1 depicts an illustrative electronic device 100 having a display, atouch sensor, and an integrated haptic stack with a user interfacepresenting several controls on the display. Electronic devices 100include electronic book readers, cellular phones, portable mediaplayers, cash registers, personal computers, tablet computers, netbooks,laptops, desktops, kiosks, and so forth.

The electronic device 100 includes a display 102, described in moredepth below with regards to FIG. 2, configured to present information toa user. Approximately perpendicular to the long axis of the display iscross sectional line “X,” with cross sections discussed below withregards to FIGS. 3-4.

As illustrated, the electronic device 100 includes a touch sensor 104for receiving user input. This touch sensor 104 may be adjacent to orintegrated with the display 102 to form a touchscreen. For descriptivepurposes, three controls in the form of virtual buttons 106(1)-(3) arepresented on the display 102 that, when activated, allow the user tolookup a contact, read a book, or open a browser. Haptic output 108 isdesignated with broken lines, and is generated by an integrated hapticstack 110. The integrated haptic stack 110 incorporates one or morepiezoelectric haptic actuators 112(1)-(P) that are configured togenerate a haptic, or vibrotactile, output which may be felt by a user114. The haptic output 108, for example, may simulate the tactileexperience of the user pushing the button 106 to “read a book” as if thebutton was an actual mechanical button.

The integrated haptic stack 110 incorporates the piezoelectric hapticactuators 112(1)-(P) on a substrate, which may or may not be shared withanother component of the device, such as the display 102. Suchincorporation may improve propagation of the haptic output 108 to theuser 114, reduce bulk of the electronic device 100, minimize partscount, reduce production costs, and so forth. The integrated hapticstack 110 is described in more depth below with regards to FIGS. 3-4.

FIG. 2 is a block diagram 200 of example internal components of theillustrative electronic device 100. In a very basic configuration, thedevice 100 includes or accesses components such as a processor 202 andone or more peripherals 204. Each processor 202 may itself comprise oneor more processors.

Peripherals 204 couple to the processor 202. A display controller 206 isshown coupled to one or more displays 102. These displays may comprisedrive electronics, such as a display drive matrix configured to affectindividual pixels within the display 102. In some implementations,multiple displays may be present and may couple to the displaycontroller 206. These multiple displays may be located in the same ordifferent enclosures or panels. Furthermore, one or more displaycontrollers 206 may couple to the multiple displays.

The display 102 may present content in a human-readable format to auser. The display 102 may comprise electrophoretic, interferometric,cholesteric, or other stable display technology which retains an imagewith no or little power applied to the display drive matrix. In otherimplementations, an active display such as a liquid crystal display,plasma display, light emitting diode display, and so forth may be used.

When multiple displays are present, these displays may be of the same ordifferent types. For example, one display may be an electrophoreticdisplay while another may be a light emitting diode display.

For convenience only, the display 102 is shown in a generallyrectangular configuration. However, it is understood that the display102 may be implemented in any shape, and may have any ratio of height towidth. Also, for stylistic or design purposes, the display 102 may becurved or otherwise non-linearly shaped. Furthermore the display 102 maybe flexible and configured to fold or roll.

The content presented on the display 102 may take the form of electronicbooks or “eBooks.” For example, the display 102 may depict the text ofthe eBooks and also any illustrations, tables, or graphic elements thatmight be contained in the eBooks. The terms “book” and/or “eBook”, asused herein, include electronic or digital representations of printedworks, as well as digital content that may include text, multimedia,hypertext, and/or hypermedia. Examples of printed and/or digital worksinclude, but are not limited to, books, magazines, newspapers,periodicals, journals, reference materials, telephone books, textbooks,anthologies, instruction manuals, proceedings of meetings, forms,directories, maps, web pages, and so forth. Accordingly, the terms“book” and/or “eBook” may include any readable or viewable content thatis in electronic or digital form.

The electronic device 100 further includes a touch sensitive inputdevice. In one implementation, the touch sensor 104 may be placed behindthe display, such that user input through contact or gesturing relativeto the display 102 may be received. In another implementation, the touchsensor 104 may be placed in front of the display 102, or in another partof the device altogether.

The electronic device 100 may have an input device controller 208configured to accept input from the touch sensor, keypad, keyboard, orother user actuable controls 210. These user actuable controls 210 mayhave dedicated or assigned operations. For instance, the actuatablecontrols 112 may include page turning buttons, a joystick, navigationalkeys, a power on/off button, selection keys, joystick, and so on.

The peripherals 204 may include a USB host controller 212. The USB hostcontroller 212 manages communications between devices attached to auniversal serial bus (“USB”) and the processor 202 and otherperipherals.

FIG. 2 further illustrates that the electronic device 100 includes atouch sensor controller 214. The touch sensor controller 214 may coupleto the processor 202 via the USB host controller 212 (as shown). Inother implementations the touch sensor controller 214 may couple to theprocessor via the input device control 208, inter-integrated circuit(“I²C’), universal asynchronous receiver/transmitter (“UART”), serialperipheral interface bus (“SPI”), or other interface. The touch sensorcontroller 214 also couples to the touch sensor 104.

The touch sensor controller 214 is configured to accept input from thetouch sensor 104 to determine characteristics of interaction with thetouch sensor. These characteristics may include the location of one ormore touches on the touch sensor 104, magnitude of the force, shape ofthe touch, and so forth.

A haptic controller 216 may couple to the USB host controller 212. Inanother implementation, the haptic controller 216 may couple to anotherinterface within the electronic device 100. The haptic controller 216couples to the piezoelectric haptic actuators 112(1)-(P). As describedabove, the piezoelectric haptic actuators 112(1)-(P) provide hapticoutput to the user 114.

The USB host controller 212 may also couple to a wireless module 218 viathe universal serial bus. The wireless module 218 may allow forconnection to wireless local or wireless wide area networks (“WWAN”).The wireless module 218 may include a modem 220 configured to send andreceive data wirelessly and one or more antennas 222 suitable forpropagating a wireless signal. In other implementations, a wired networkinterface may be provided.

The electronic device 100 may also include an external memory interface(“EMI”) 224 coupled to external memory 226. The EMI 224 manages accessto data stored in the external memory 226. The external memory 226 maycomprise Static Random Access Memory (“SRAM”), Pseudostatic RandomAccess Memory (“PSRAM”), Synchronous Dynamic Random Access Memory(“SDRAM”), Double Data Rate SDRAM (“DDR”), Phase-Change RAM (“PCRAM”),or other computer-readable storage media.

The external memory 226 may store an operating system 228 comprising akernel 230 operatively coupled to one or more device drivers 232. Thedevice drivers 232 also operatively couple to the peripherals 204. Theexternal memory 226 may also store data 234, which may comprise contentfor consumption on the electronic device 100, executable programs,databases, user settings, configuration files, device status, and soforth. As shown, the external memory 226 may store a haptic synthesizermodule 236 configured to generate commands for the haptic controller216, which in turn generates haptic output 108 via the piezoelectrichaptic actuators 112(1)-(P).

The electronic device 100 may include one or more other, non-illustratedperipherals, such as a hard drive using magnetic, optical, or solidstate storage to store information, a firewire bus, a Bluetooth™wireless network interface, camera, global positioning system, PC Cardcomponent, sound interface, and so forth.

One or more batteries 238 may provide operational electrical power tocomponents of the electronic device 100 for operation when the device isdisconnected from a power supply 240. Operational electrical power issufficient to provide for operation of the device, as distinguished fromthe lesser electrical power requirements of a sleep or state retentionmode. The power supply 240 may be internal or external to the electronicdevice 100. The power supply 240 is configured to provide operationalpower for electronic device 100, charge the battery 238, or both.“Battery” as used in this application includes components capable ofacting as a power source to an electronic device. Power sources includechemical storage cells such as lithium polymer batteries, charge storagedevices such as ultracapacitors, fuel cells, and so forth.

Couplings, such as that between haptic controller 216 and the USB hostcontroller 212, are shown for emphasis. There are couplings between manyof the components illustrated in FIG. 2, but graphical arrows areomitted for clarity of illustration.

FIG. 3A depicts an enlarged cross section 300 of one implementation ofthe electronic device of FIG. 1 along line “X”. The display 102comprises one or more presentation layers 302 and a display substrate304. As described above, the display 102 may incorporate a touch sensor104 above or below the display. For clarity of illustration, but not asa limitation, the touch sensor 104 is omitted.

The presentation layers 302 generate the image a user sees and maycomprise an electrophoretic slurry, liquid crystals, light emittingdiodes, and so forth. The display substrate 304 may comprise an activedisplay drive matrix used in conjunction with the presentation layers302 to generate an image for presentation the user.

The display substrate 304 comprises two sides, which are opposite oneanother and substantially parallel to one another. A first side isadjacent to the presentation layers 302, while the second side is on theside opposite. In traditional assemblies, this second side is unused. Asshown here, however, a piezoelectric haptic actuator 112 affixes to thesecond side of the display substrate 304. In some implementations, thesecond side may comprise a conductor to provide an electrical path tothe piezoelectric haptic actuators 112(1)-(P).

The affixing of the piezoelectric haptic actuator 112 to the second sideof the display substrate 304 may involve lamination, application ofheat, direct deposition, and so forth. Thus, the piezoelectric hapticactuator 112 becomes a part of the display substrate 304. FIG. 3B showsthe cross section 306 of the integrated haptic stack 110. The assembledstack provides a low profile, small form factor device while reducingpart count. Additionally, the placement of the piezoelectric hapticactuators 112(1)-(P) on the display substrate 304 provides a mechanicalpath suitable for the propagation of physical forces to the user via thedisplay 102. Thus, a user touching the display 102 may also feel thegenerated haptic output 108.

While the display substrate 304 is depicted here, in otherimplementations portions of other components may be used as a substratefor the piezoelectric haptic actuators 112(1)-(P). For example, abattery casing, a portion of a device enclosure, and so forth may serveas a substrate for the piezoelectric haptic actuators 112(1)-(P).

FIG. 4A illustrates a cross section 400 of an alternative implementationof an integrated haptic stack. In this implementation, the piezoelectrichaptic actuator 112 is affixed to a haptic substrate 402 to form ahaptic assembly 404. In one implementation, the haptic substratecomprises a foil or thin film of stainless steel or another conductivematerial. The piezoelectric haptic actuator 112 may be affixed, bonded,laminated, fired, deposited, and so forth onto the haptic substrate 402.In some implementations, a perimeter of the haptic substrate 402 may bedisposed to correspond to a perimeter of the display 102.

In some implementations, piezoelectric haptic actuators 112 may bedisposed on both sides of the haptic substrate 402. Such an arrangementincreases a stroke length and force output of the haptic assembly 404when the piezoelectric haptic actuators 112 are active.

FIG. 4B depicts the cross section 406 after assembly depicting theintegrated haptic stack 110. As above, this integration allows for amechanical path suitable for the propagation of physical forces from thepiezoelectric haptic actuators 112 to the user via the display 102.Other advantages include a low profile and ease of construction andvariability between models. For example, the haptic assembly 404 may beoptional on some models of the electronic device 100. Due to the smallform factor and ease of insertion during assembly, the haptic assembly404 may be included or omitted depending upon the desired option.

FIG. 5 illustrates a plan view 500 of a single piezoelectric hapticactuator on a substrate. As described above, the substrate may comprisethe display substrate 302, another substrate shared with anothercomponent, such as an enclosure or battery casing, or the hapticsubstrate 402.

In this illustration a single circular geometry piezoelectric hapticactuator 112 is depicted, disposed approximately in the center of thesubstrate. In some implementations, the positioning of the piezoelectrichaptic actuator 112 may be varied depending upon the mechanicalcharacteristics of adjacent structures. For example, the piezoelectrichaptic actuator 112 may be disposed on the substrate closest to aninternal support member to provide a better path for propagation of thehaptic output 108.

The substrate may comprise a conductive surface, having one or moreelectrically conductive contact pads 502. In this example, four contactpads 502(1)-(4) are depicted at four corners of the substrate. In otherimplementations, the number of contact pads 502(1)-(X) and/or positionmay vary. In other implementations, the substrate may be non-conductive,and a conductive layer may be incorporated into the piezoelectric hapticactuator 112.

FIG. 5 also illustrates that the piezoelectric haptic actuator 112includes a piezoelectric active area 504. This area contains thepiezoelectric material used to generate the force output. An electricalcontact pad 506 resides within or in contact with the piezoelectricactive area 504. While this figure illustrates a single electricalcontact pad 506, in some implementations multiple electrical contactpads 506 may be present within or in contact with the piezoelectricactive area 504. Additionally, in some implementations the contacts 506,502, or both may be distributed along the sides or edges.

A combination of the electrical contact pad 502 and the electricalcontact pad 506 are used to deliver electrical signals to thepiezoelectric active area 504. These electrical signals in turn generatethe physical displacement of the piezoelectric material which in turnresults in a transfer of momentum, deformation, dislocation, or acombination thereof which is perceived by the user as the haptic output108.

The haptic controller 216 as described above generates the electricalsignals themselves. These signals may vary in polarity, voltage,waveform, and so forth. Conductors 508 convey the electrical signals tothe electrical contact pads 502 and 506. These conductors may comprisewires, circuit traces, and so forth.

FIG. 6 illustrates a plan view 600 of dual piezoelectric hapticactuators on a substrate. As described above, multiple piezoelectrichaptic actuators 112 may be used to generate haptic output 108. In thisillustration, two circular geometry piezoelectric haptic actuators112(1)-(2) are presented. As described above, they are coupled via theconductors 508 to the haptic controller 216.

FIG. 7 illustrates a plan view 700 of six piezoelectric haptic actuatorson a substrate. In this illustration, the piezoelectric haptic actuatorsare distributed in a regular array or matrix on the surface of thesubstrate. In other implementations the distribution may differ. In someimplementations the haptic controller 216 may independently address oneor more of the piezoelectric haptic actuators 112. For example, thehaptic controller 216 may generate output from the piezoelectric hapticactuators 112(1), (4), and (5) while the other non-specified actuators112(2), (3), and (6) remain inactive. Variable addressing may be used tovary the nature and magnitude of the haptic output 108.

FIG. 8 illustrates a plan view 800 of five piezoelectric hapticactuators with different geometries on a substrate. The count,distribution, and geometry of the actuators may be adjusted to accountfor variations in compliance of the substrate, desired outputcharacteristics, and so forth.

The piezoelectric haptic actuators may manifest in one of many possiblegeometries. The different geometries may be determined according todesired output characteristics, space available on the substrate, orother factors. A selection of possible geometries is depicted. Arectangular piezoelectric haptic actuator 112(1) is shown with roundedcorners. Rounded corners as well as generally arcuate forms may reducelocalized stresses generated by movement of the piezoelectric material.By reducing localized stresses, longevity of the actuator 112 isimproved.

An elliptical piezoelectric haptic actuator 112(3) is depicted, as wellas a pair of circular piezoelectric haptic actuators 112(4) and (5) ofdiffering sizes. Specific ratios of actuator sizes may be used toproduce a range of desired outputs. For example, as shown here the largecircular piezoelectric haptic actuator 112(5) has a diameterapproximately three times that of the small circular piezoelectrichaptic actuator 112(4). In other implementations, other geometries maybe used.

FIG. 9 depicts a plan view 900 of additional geometries of piezoelectrichaptic actuators on a substrate. In some implementations thepiezoelectric haptic actuators 112(1) may describe an approximatelytoroidal shape, such as depicted in this figure. The toroid may form acomplete ring such as shown with regards to piezoelectric hapticactuator 112(1) or be split as shown with regards to the piezoelectrichaptic actuator 112(2). In some implementations the split of the ringmay be such that the halves are equal, such as shown here, while inother implementations the split may be more or less. Furthermore in someimplementations, ring sections may nest within one another on thesubstrate.

FIG. 10 illustrates an example process 1000 that may be implemented withthe architectures of FIGS. 1-9 or by other architectures. This processis illustrated as a collection of blocks in a logical flow graph, whichrepresent a sequence of operations that can be implemented in hardware,software, or a combination thereof. In the context of software, theblocks represent computer-executable instructions that may be stored onone or more computer-readable storage media and that, when executed byone or more processors, perform the recited operations. Generally,computer-executable instructions include routines, programs, objects,components, data structures, and the like that perform particularfunctions or implement particular abstract data types. The order inwhich the operations are described is not intended to be construed as alimitation, and any number of the described blocks can be combined inany order or in parallel to implement the processes.

FIG. 10 illustrates a process 1000 of forming an integrated haptic stackwith a shared substrate. Operation 1002 depicts acquiring a substratehaving a first side and a second side opposite the first side.

Operation 1004 affixes the piezoelectric haptic actuator 112 to thefirst side. As described above, the affixing may comprise bonding,lamination, firing, depositing, and so forth onto the substrate. In someimplementations, the substrate and a component may be joined together asdescribed below before the affixation of the piezoelectric hapticactuators 112.

At 1006 the component is joined to the second side of the substrate. Forexample, where the substrate comprises the display substrate 304, thepresentation layer 302 component may be joined to the second side. Oncejoined, an integrated haptic stack is formed, incorporating a pluralityof functions. Where the component comprises a presentation layer and theresulting substrate and second component produce a display, the twofunctions of the integrated haptic stack are thus the display functionand the haptic output function.

CONCLUSION

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described. Rather,the specific features and acts are disclosed as illustrative forms ofimplementing the claims. For example, the methodological acts need notbe performed in the order or combinations described herein, and may beperformed in any combination of one or more acts.

What is claimed is:
 1. An electronic device, comprising: a processor; adisplay coupled to the processor to render content on the electronicdevice, the display comprising a display substrate and a presentationlayer disposed adjacent to a first side of the display substrate; ahaptic assembly disposed on a second side of the display substratesubstantially opposite the first side of the display substrate, thehaptic assembly comprising: a haptic substrate; and one or morepiezoelectric haptic actuators disposed between the haptic substrate andthe display substrate on a first side of the haptic substrate; and ahaptic controller coupled to the processor and configured to drive theone or more piezoelectric haptic actuators.
 2. The electronic device ofclaim 1, wherein the one or more piezoelectric haptic actuators, whendriven by the haptic controller, impart a physical force on at least aportion of a structure of the electronic device and generate a resultingtransfer of momentum between the structure and a user.
 3. The electronicdevice of claim 1, wherein the one or more piezoelectric hapticactuators, when driven by the haptic controller, impart a physical forceon at least a portion of a structure of the electronic device andgenerate a resulting dislocation or deformation of the structure.
 4. Theelectronic device of claim 1, wherein the one or more piezoelectrichaptic actuators, when driven by the haptic controller, simulate atactile experience.
 5. The electronic device of claim 1, wherein thedisplay comprises a touch sensor coupled to the processor and configuredto accept user input to manipulate the content rendered by the display.6. The electronic device of claim 5, wherein the haptic controller isconfigured to drive the one or more piezoelectric haptic actuators inresponse to the touch sensor accepting the user input to manipulate thecontent rendered by the display.
 7. The electronic device of claim 5,wherein: the user input is received at a particular location of thetouch sensor corresponding to a particular location of the display; andthe haptic controller is configured to drive the one or morepiezoelectric haptic actuators at the particular location of the displayin response to the touch input.
 8. The electronic device of claim 1,wherein the haptic controller is further configured to generate a hapticoutput via the one or more piezoelectric haptic actuators.
 9. Theelectronic device of claim 1, wherein the presentation layer comprisesan electrophoretic slurry.
 10. The electronic device of claim 1, whereinthe one or more piezoelectric haptic actuators comprises a ceramicmaterial.
 11. The electronic device of claim 1, wherein the one or morepiezoelectric haptic actuators comprises a polymer material.
 12. Ahaptic output device comprising: a plurality of piezoelectric actuatorsdisposed on a first side of a substrate and configured to, whenactivated, impart a physical force on at least a portion of a structureto generate a haptic output, wherein the plurality of piezoelectricactuators comprises two or more sizes different from one another; one ormore additional piezoelectric actuators disposed on a second side of thesubstrate that is substantially opposite the first side, wherein the oneor more additional piezoelectric actuators increase at least one of astroke length and a force output associated with the haptic output whenthe plurality of piezoelectric actuators disposed on the first side ofthe substrate are active; and a plurality of electrical conductorsconfigured to couple the plurality of piezoelectric actuators and theone or more additional piezoelectric actuators to a haptic controllerconfigured to activate individual piezoelectric actuators.
 13. Thehaptic output device of claim 12, wherein the plurality of piezoelectricactuators disposed on the first side of the substrate comprises two ormore geometries different from one another, each geometry associatedwith a different haptic output characteristic.
 14. The haptic outputdevice of claim 12, wherein the plurality of piezoelectric actuatorscomprises two or more compositions different from one another.
 15. Amethod of assembling an integrated haptic stack for insertion into anelectronic device having a structure, the method comprising: affixing ahaptic assembly to a first side of a display substrate having the firstside and a second side opposite the first side, wherein: the hapticassembly comprises a haptic substrate and a piezoelectric hapticactuator disposed between the haptic substrate and the displaysubstrate; and the piezoelectric haptic actuator is configured to, whenactive, impart a physical force on at least a portion of the structureof the electronic device to generate a haptic output; and joining acomponent of the electronic device to the second side of the displaysubstrate to form the integrated haptic stack.
 16. The method of claim15, wherein the second side of the display substrate comprises an activedisplay drive matrix and the component of the electronic devicecomprises an electrophoretic display layer coupled to the active displaydrive matrix.
 17. The method of claim 15, wherein the first side of thedisplay substrate and the second side of the display substrate aresubstantially planar and parallel to one another.
 18. The method ofclaim 15, wherein the affixing comprises firing the haptic assembly tothe first side of the display substrate.
 19. The method of claim 15,wherein the joining comprises laminating the component of the electronicdevice to the second side of the display substrate.
 20. The electronicdevice of claim 1, wherein a perimeter of the haptic substrate isdisposed to correspond to a perimeter of the display.
 21. The electronicdevice of claim 1, wherein: the haptic assembly further comprises one ormore additional piezoelectric haptic actuators that are disposed on asecond side of the haptic substrate that is substantially opposite thefirst side of the haptic substrate; and the one or more additionalpiezoelectric haptic actuators increase a stroke length and a forceoutput of the haptic assembly when the one or more piezoelectric hapticactuators disposed between the haptic substrate and the displaysubstrate on the first side of the haptic substrate are active.
 22. Theelectronic device of claim 1, wherein the one or more piezoelectrichaptic actuators include a plurality of piezoelectric haptic actuators,and at least one of: the plurality of piezoelectric haptic actuatorsinclude two or more sizes different from one another and able to providedifferent haptic output characteristics; or the plurality ofpiezoelectric haptic actuators include two or more geometries differentfrom one another and able to provide different haptic outputcharacteristics.
 23. The haptic output device of claim 12, wherein theone or more additional piezoelectric actuators disposed on the secondside of the substrate comprises two or more sizes different from oneanother, each size associated with a different haptic outputcharacteristic.
 24. The haptic output device of claim 12, wherein theone or more additional piezoelectric actuators disposed on the secondside of the substrate comprises two or more geometries different fromone another, each geometry associated with a different haptic outputcharacteristic.